1. Field of the Invention
The present invention is related to the correction of artifacts in image processing and, more specifically, to the reduction of high absorption object artifacts in computed tomography.
2. Discussion of Background
There have been many different approaches to minimizing artifacts from high absorption objects, such as metal pins, in medical images. H. K. Tuy in An Algorithm to Reduce Clip Artifacts in CT Images, SPIE vol. 1652 Med. Imaging VI: Image Processing pp. 635-43 (1992), and in A post-processing algorithm to reduce metal clip artifacts in CT images, Eur. Radio. 3, 129-134 (1993) describes a two-phase algorithm where first a crude compensation for beam hardening is performed followed by a refinement phase. Kalender et al, Reduction of CT Artifacts Caused by Metallic Implants, Radiology, vol. 164, no. 2, pp. 576-7 (1987) describes an artifact reduction routine where the metallic implant is delineated by an operator on the image using a light pen. Approaches also include image processing, iterative reconstruction, beam hardening correction and partial volume correction. While the last two correction techniques of the above-mentioned methods have been used to improve image quality, prior methods have not been effective in handling metal pin artifacts, especially severe metal pin artifacts such as star pattern artifacts, streak artifacts and blooming artifacts, nor have they been effective in recovering diagnostic information obscured by these artifacts.